Table 1. Selected anthropometric, clinical and laboratory features of the patients studied.
| Disease Features | SS (n = 43) | SLE (n = 27) | RA (n = 14) |
| Age, years, median (range) | 52.5 (33–67) | 37.5 (19–45) | 60.0 (38–75) |
| Sex, female:male | 43∶0 | 25∶2 | 7∶7 |
| Disease duration, years, median (range) | 11 (2–23) | 11 (1–20) | 10 (1–17) |
| Sicca man manifestations, no. positive (%) | 43 (100) | 0 (0.0) | 0 (0.0) |
| Disease activity, median (range) a | 9 (0–41) | 4 (0–16) | 5.2 (3.5–7.0) |
| Disease severity, median (range) a | 2 (2–11) | 2 (0–6) | 2.9 (1.3–5.4) |
| Type-I SS disease, no. positive (%) a | 25 (58.1) | NA | NA |
| ANA, titer-1, median (range) | 320 (0–2560) | 640 (0–2560) | 0 |
| Anti-Ro/SSA, no. positive (%) | 29 (67.4) | 15 (40.5) | 0 (0.0) |
| Anti-La/SSB, no. positive (%) | 13 (30.2) | 0 (0.0) | 0 (0.0) |
| Anti-dsDNA, no. positive (%) | 0 (0.0) | 18 (47.4) | 0 (0.0) |
| Anti-chromatin, no. positive (%) | 0/27 (0.0) | 4/19 (21.1) | 0 (0.0) |
| Anti-histone, no. positive (%) | 0/27 (0.0) | 5/19 (26.3) | 0 (0.0) |
| Low serum C3 and/or C4, no. positive (%) b | 18 (41.9) | 23 (60.5) | 0 (0.0) |
| Low serum C1q, no. positive (%) c | 5/17 (29.4) | 5/15 (33.3) | ND |
| Rheumatoid factor, no. positive (%) | 20 (46.5) | ND | 11 (78.6) |
a: disease activity, disease severity and Type-I SS disease were defined as described in Patients and Methods,
b: low serum C3<90 mg/dl and C4<20 mg/dl,
c: low serum C1q<15 mg/dl, NA: not applicable, ND: not done.